No else.  So, in a list that mixes numeric and other content, we ignore the non-numeric entries but still increase count for each of them.  The result won't be meaningful (e.g. it won't be the mean or variance of the numeric entries, nor what you would get with zero in place of each non-numeric entry); it'll match what you would have obtained had each non-numeric entry in the list been replaced with the mean of the earlier numeric entries.  I really think it would be better to barf out if we're asked for mean or variance of a list whose entries aren't all numeric: i.e. <code> else { return FnFailure(); } </code> here.